Recombinant Type A and B Phytochromes from Potato. Transient Absorption Spectroscopy

Ruddat, Antje; Schmidt, P.; Gatz, Christiane; Braslavsky, Silvia E.; Gärtner, Wolfgang; Schaffner, Kurt

doi:10.1021/bi962012w

Cited by 58 publications

(57 citation statements)

References 37 publications

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“…Hence, characterization of the molecular interaction between the chromophore and the apoprotein is crucial for understanding the functional mechanism(s) of phytochromes. Several studies have addressed this interaction by using in vitro assembly of PHYA (5,28,29,47), PHYB (35,37,48), PHYC and PHYE (43), or apoprotein mutants (30)(31)(32). However, in contrast to the vertebrate photoreceptor rhodopsin (49), in the phytochrome field, little has been done to examine the relationships among chromophore structure, its assembly to apoprotein, and photochromism of the holoprotein, because of the difficulty of synthesizing the chromophore and its structural analogs.…”

Section: Discussionmentioning

confidence: 99%

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In vitro assembly of phytochrome B apoprotein with synthetic analogs of the phytochrome chromophore

Hanzawa

Inomata

Kinoshita

et al. 2001

Proc. Natl. Acad. Sci. U.S.A.

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Phytochrome B (PhyB), one of the major photosensory chromoproteins in plants, mediates a variety of light-responsive developmental processes in a photoreversible manner. To analyze the structural requirements of the chromophore for the spectral properties of PhyB, we have designed and chemically synthesized 20 analogs of the linear tetrapyrrole (bilin) chromophore and reconstituted them with PhyB apoprotein (PHYB). The A-ring acts mainly as the anchor for ligation to PHYB, because the modification of the side chains at the C2 and C3 positions did not significantly influence the formation or difference spectra of adducts. In contrast, the side chains of the B-and C-rings are crucial to position the chromophore properly in the chromophore pocket of PHYB and for photoreversible spectral changes. The side-chain structure of the D-ring is required for the photoreversible spectral change of the adducts. When methyl and ethyl groups at the C17 and C18 positions are replaced with an n-propyl, n-pentyl, or n-octyl group, respectively, the photoreversible spectral change of the adducts depends on the length of the side chains. From these studies, we conclude that each pyrrole ring of the linear tetrapyrrole chromophore plays a different role in chromophore assembly and the photochromic properties of PhyB.

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Section: Discussionmentioning

confidence: 99%

“…In contrast, PhyB has not been well characterized because of its low abundance in native tissue. Recently, several groups reported in vitro assembly of PhyB and showed that it has similar spectral properties to PhyA (35)(36)(37).…”

mentioning

confidence: 99%

In vitro assembly of phytochrome B apoprotein with synthetic analogs of the phytochrome chromophore

Hanzawa

Inomata

Kinoshita

et al. 2001

Proc. Natl. Acad. Sci. U.S.A.

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“…Several groups have reported in vitro assembly of PhyB and have shown that it has similar spectral properties to PhyA. [134][135][136] To analyze the structural requirements of the chromophore for the spectral properties of PhyB, we designed and chemically synthesized more than 20 bilin chromophore derivatives (Fig. 10), including natural PÈB and PCB, and reconstituted them with recombinant Arabidopsis PhyB apoprotein (PHYB) through collaborative study with biologists.…”

Section: Assembly Of the Synthetic Bilin Chromophoresmentioning

confidence: 99%

Studies on the Structure and Function of Phytochromes as Photoreceptors Based on Synthetic Organic Chemistry

Inomata

2008

Bulletin of the Chemical Society of Japan

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“…Arabidopsis phyB transcripts were probed with a 3.9-kb KpnI fragment generated from pMAB316 and potato phyB transcripts with a 2.7-kb HpaI/ KpnI fragment of a plasmid encoding the full-length cDNA (Ruddat et al, 1997). Probes against the potato ribosomal protein S4 (Devi et al, 1989) served to normalize for equal loading of poly(A ϩ ) RNA.…”

Section: Rna Extraction and Northern Analysismentioning

confidence: 99%

Heterologous Expression of Arabidopsis Phytochrome B in Transgenic Potato Influences Photosynthetic Performance and Tuber Development1

et al. 1999

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Transgenic potato (Solanum tuberosum) plants expressing Arabidopsis phytochrome B were characterized morphologically and physiologically under white light in a greenhouse to explore their potential for improved photosynthesis and higher tuber yields. As expected, overexpression of functional phytochrome B caused pleiotropic effects such as semidwarfism, decreased apical dominance, a higher number of smaller but thicker leaves, and increased pigmentation. Because of increased numbers of chloroplasts in elongated palisade cells, photosynthesis per leaf area and in each individual plant increased. In addition, photosynthesis was less sensitive to photoinactivation under prolonged light stress. The beginning of senescence was not delayed, but deceleration of chlorophyll degradation extended the lifetime of photosynthetically active plants. Both the higher photosynthetic performance and the longer lifespan of the transgenic plants allowed greater biomass production, resulting in extended underground organs with increased tuber yields.Plant growth, development, and metabolic activities are regulated by a range of environmental factors, including light, which is of central importance. Light is perceived by a variety of photoreceptors that control developmental processes such as germination, photomorphogenesis, flowering, and senescence, as well as metabolic processes such as photosynthesis and assimilate allocation. It has been pointed out before that the agricultural productivity of crop plants might be enhanced by overexpressing one of these central regulators (Smith, 1992), and phytochromes are promising candidates for such an improvement (Robson et al., 1996).Phytochromes represent a family of red-light-absorbing photoreceptors that can exist in the physiologically inactive Pr form and the active Pfr form (for reviews, see Quail et al., 1995;Smith, 1995; Casal et al., 1998). Pr and Pfr are interconvertible by red or FR light, respectively. This absorption profile is extremely useful for the detection of shade or the presence of neighboring plants. At high relative proportions of FR radiation, which occur under shade conditions or in dense plant populations, the photoequilibrium is shifted toward the inactive Pr form. Under these conditions, green plants exhibit various symptoms of the shade-avoidance response, such as promotion of stem and petiole elongation, reduced leaf thickness, reduced chlorophyll synthesis, and increased apical dominance (Smith and Whitelam, 1997). The shade-avoidance response reduces the availability of resources for storage and reproduction.Five PHY genes have been identified in Arabidopsis that have 50% to 80% identity at the amino acid level (Sharrock and Quail, 1989;Clack et al., 1994). The best-characterized members are PHYA and PHYB. phyA accumulates in the dark and is rapidly degraded upon conversion to the labile Pfr form (Pratt et al., 1997). It is responsible for detecting continuous FR light and dampens the shade-avoidance response under high relative proportions of FR light (McCo...

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Recombinant Type A and B Phytochromes from Potato. Transient Absorption Spectroscopy

Cited by 58 publications

References 37 publications

In vitro assembly of phytochrome B apoprotein with synthetic analogs of the phytochrome chromophore

In vitro assembly of phytochrome B apoprotein with synthetic analogs of the phytochrome chromophore

Studies on the Structure and Function of Phytochromes as Photoreceptors Based on Synthetic Organic Chemistry

Heterologous Expression of Arabidopsis Phytochrome B in Transgenic Potato Influences Photosynthetic Performance and Tuber Development1

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